Close-up images of Mars by the Mariner 9 probe indicated networks of valleys that looked like the stream beds on Earth. These images also implied that Mars once had an atmosphere that was thick enough to trap the sun's heat. If this were true, something happened to Mars billions of years ago that stripped away the planet's atmosphere. This paragraph best supports the statement that

Comments and Answers (2)

Andy

Andy

What is the correct solution?

Andy

Andy

What is the correct solution?

Avatar

{{SampleComment.userName || "Your Name"}} ~ {{SampleComment.userCity}}

{{SampleComment.commentValue || "Your Answer or Comment goes here...."}}